A second-place finish in Nevada, a major endorsement in South Carolina, a strong debate Tuesday and a pair of polls showing him with a staggering lead here have given new hope to his campaign. Money is flowing anew into his war chest, as well as to a super PAC supporting him.

Armed with those data points, the campaign and super PAC are telling donors that Biden — given his strength among African-American voters and momentum kicking in at the right time — is quickly emerging as the alternative to frontrunner Bernie Sanders.

“The debate was really a huge turning point,” said Amanda Loveday, a senior adviser with the PAC and former director of the South Carolina Democratic Party. Donors who had pulled back from Biden, wondering whether Mike Bloomberg would claim the moderate mantle, have started digging into their pockets again, she said. “That got them off their hands.”

And it got rank-and-file voters on their feet.